There are known client/server systems for connecting an application server and a client terminal by way of a network to allow the client to log in at the server machine from an application for connection of the client terminal in order to display and operate an application held by the server. In such a system, medical display information and information for user operations are transmitted to the client terminal by means of a same network protocol.
For example, a mouse click or a keyboard operation at the client terminal is hooked by the application for connection and the operation event is transmitted to the server. The server executes a process (e.g., of calling an image or inputting character information) that corresponds to the received operation event and the medical display information is transmitted from the server to the application for connection on the client terminal by way of the network. The medical display information is rendered into an image, which is then displayed and updated on the terminal by utilizing the display resource of the client terminal.
In a client/server system as described above, if it is held in a LAN environment where bands exceeding 100 M-bit/second exist, the network bands are occupied to a large extent as a result of displaying and updating large volume images as moving images are reproduced and/or three-dimensional CAD software for editing/viewing a three-dimensional image from various angles is utilized so that consequently the processing speed does not catch up the volume of data to be processed. Then, there arises a problem that the user operation instruction from the terminal delays to give rise to a degraded user response. Additionally, if a single communication protocol for display is employed in a network environment from the server down to the terminal, there also arise problems including that the secure communication encoding/decoding cost becomes high and that the performance is damaged for patient information.